it would be good if i could switch my auto focus lens to manual and it do the focus trap thing

Hi John,

You can disable your AF lens to use trap focusing on any Pentax DSLR. You have to short the Data Pin which is the farthest pin from the lens lock pin, and the closest to the screw drive AF shaft. This is easily done with a strip of aluminum foil -- it must be conductive to short the pin, not insulate it as a piece of tape would. All Auto Exposure functions are retained -- the camera thinks that you're shooting an "A" series lens (as this pin is missing on them, and the lens mount shorts the pin in the camera). This mod also allows you to enter the corrected FL of the lens to the SR system if you use a TC since no lens ID or FL info is passed from the lens -- which also means that you have to remember to enter the correct FL if you don't use a TC. . .